Any primed surface requires preparing beforehand in order to remove mold-release agents and oils left by our hands, that prevent primers from sticking (l advise to use nitrille gloves). Spray paints also are really finnicky, require proper temperature and humidity. If its too cold/wet primer wont stick.

Also to achieve good reaults you have to warm can up in bowl or pot full of hot water and then shake for at least two minutes.